WHY IT'S SO HARD TO GET PERVS OUT OF POLITICS.

POLITICS IS A high-stakes, winner-takes-all game with irresistible appeal to a certain kind of low-quality human being. There are typically only two viable candidates in any national race, and voters have a lot invested in the idea that bad things will happen if their guy loses.

That means that if their guy turns out to be, say, an unrepentant pedophile, there will be plenty of voters who pause for a minute and wonder whether having an unrepentant pedophile in office who will consistently vote the way they want is worse or better than having a non-pedophile who will consistently vote in a way that they believe will undermine the American experiment. Partisan duopoly creates powerful incentives to wear blinders about the flaws of your preferred candidate, and to make excuses for failings too glaring to deny.

In more concrete terms, voters feel compelled to calculate whether a dubious non-consensual boob grab caught on camera is worth accepting in order to get a decade of votes against Republican Supreme Court nominees, in the case of Sen. Al Franken (D-Minn.). Or whether a few sexual harassment settlements paid by taxpayers are a price they're willing to bear in exchange for a vote against Obamacare repeal, as in the case of Rep. John Conyers (D-Mich.). This non-Euclidean electoral geometry was most famously employed on behalf of Bill Clinton decades ago by his feminist supporters, who were willing to dismiss behavior ranging from a voluntary affair with an intern to much more serious allegations of rape and assault, because they believed he would defend women's rights more effectively than his would-be replacements.

South Park famously depicted formal political debates as moronic shoutfests between a giant douche and a turd sandwich. That's a bit of an overstatement: Not all politicians are disgusting. But when a candidate does turn out to be awful, voters often discover too late that--like visitors to Matt Lauer's office or Harvey Weinstein's hotel room--their escape routes have been blocked off. And simply refusing to participate doesn't help with this particular problem; a write-in vote for "neither" won't prevent one of the major party hopefuls from winning in the end.

Sure, politicians are ultimately answerable to the electorate. They're scared we might not vote for them next time around, and that guides their behavior. But they also know that they've made themselves extremely hard to remove by building all kinds of institutional safeguards for...